1. Field of the Invention
The present invention relates to a pipe-type heat exchange device with enhanced heat exchange properties as well as to the method of manufacturing thereof.
2. Description of the Related Art
As an example of a pipe-type heat exchange device wherein two pipes are attached to each other and wherein heat exchange of the fluids flowing through the above pipes is carried out, a heat exchange device is cited wherein a cooling water pipe leading to the connector pipe connecting the engine head bypass outlet to the water pump is positioned along an engine blow-by gas pipe and wherein the heat of the cooling water pipe is supplied to the blow-by gas pipe (refer to, for example, Japan Examined Utility Model Application Publication S64-7208).
In the pipe-type heat exchange device as described in Japan Examined Utility Model Application Publication S64-7208, both pipes are subjected to brazing and closely linked to each other in order to efficiently transfer the heat of the cooling water to the blow-by gas pipe.
Other examples of pipe-type heat exchange devices are those composed of a blow-by gas pipe and an exhaust gas reflux pipe (refer to, for example, Japan Examined Utility Model Application Publication S62-33049) or those composed of a capillary tube and a refrigerant suction side pipe of a compressor in a refrigeration circuit (refer to, for example, Japanese Patent Application Laid-open No. 2001-248979).
In some cases, since the pipes are wave-shaped and have a straightness of approximately ±0.1 mm, gaps result between the pipes even when they have been attached together. In particular, when the concave sections of the generating line in both pipes face each other and when the gaps exceed the specified gap, the solder does not persist over the above section, resulting in an inferior solder. This results in reduced heat exchange efficiency.
The pipes are temporarily held together using a stay before being placed in a furnace for brazing to be carried out. However, there are cases in which the pipes separate from each other during the above process, resulting in insufficient brazing between the pipes. This results in defective products.